The present invention relates to excavation machines.
In particular the present invention relates to machines which are used to dig a trench for a pipeline.
A conventional way of digging a trench for a pipeline requires the use of a machine which has an hydraulically controlled arm with an excavating bucket at its lower end. Earth is removed from the trench by the excavation bucket scooping up the earth and depositing it to one side.
As a result of the digging operation described above a trench is constructed of a generally rectangular cross-section.
The problem with digging a trench with a generally rectangular cross-section is that more earth is removed from the trench than actually needs to be moved in order to deposit a length of pipe in the trench. Furthermore the machinery currently available to dig trenches does not allow a long trench to be excavated at a satisfactory rate, in part because the trench is formed with a generally rectangular cross-section and this requires that the walls of the trench must be stable. Accordingly considerable effort must be exerted in order to ensure that any excavating machinery does not collapse the trench wall and this results in the limitation on the speed of movement of excavating equipment.
The present invention provides an alternative method and apparatus for digging a trench. In its preferred form the apparatus is directed to digging a trench which has a generally V-shaped or wedge-shaped cross-section with the resultant benefit that less earth needs to be removed in a trench digging operation.
According to one aspect of the present invention there is provided an apparatus for digging a trench including a cutter means for cutting through a ground surface and a guide with a loading end located rearwardly of the cutting means and adapted for guiding earth from the loading end to an off loading end as the apparatus moves in a forward direction, wherein the cutting means is adapted for cutting through a ground surface along two laterally spaced paths in front of the loading end of the guide.
Preferably the apparatus is adapted to be coupled to a vehicle which is adapted to move the apparatus.
It is preferred that the loading end of the guide is substantially at ground level.
According to the present invention there is provided an apparatus for digging a trench including a cutter means for cutting through a ground surface along two laterally spaced paths, a guide with a loading end for excavating earth between the two paths and for guiding excavated earth to its off loading end and a frame supporting the cutting means and guide and adapted for connection to a mobile carriage.
It is preferred that the frame is adapted to be pulled along behind a vehicle such as a bulldozer.
According to one version of the invention the frame is adapted to be removably connected to a vehicle.
The frame may be connected to the back of a tracked vehicle.
According to another embodiment the apparatus is part of a vehicle which is custom made with the cutting means, guide and frame operable by control componentry associated with the vehicle.
The apparatus may include control means for controlling movement of the frame, guide and cutting means.
The control means may include a parallelogram linkage which interconnects the frame and the mobile carriage.
The apparatus preferably includes pivot means for pivoting the frame with respect to the control means.
The pivot means may include at least one pivotable member which is fixed to the frame.
The control means may include at least one piston with a piston rod connected to the frame.
It is preferred that the pivot means includes left and right pivotable members.
The control means may include left and right side pistons which are respectively connected to left and right side pivotable members.
Each piston may be pivotably connected to the mobile carriage.
The cutting means may include left and right side cutting devices.
Each cutting device may be a closed loop cutting chain or wheel.
The guide may be in the form of a chute.
The chute preferably h side walls extending upwardly and outwardly from a narrow base section.
The base is preferably in the form of a narrow gutter between the side walls of the chute.
The base section is preferably V-shaped.
The chute loading end may be adapted to gouge earth from the ground and scoop up the gouged earth.
It is preferred that earth scooped up by the chute is conveyed up the chute to its off loading end by movement of the apparatus in a forward direction.
According to another variation the base section includes a conveyor which moves scooped up earth to the off loading end.
It is preferred that the chute has a front face which is sharpened at the based section to enable excavation of earth as the apparatus moves in a forward direction.
The front face preferably has a lower portion which acts as a blade or ripper to cut into the earth.
It is preferred that the chute includes a plurality of rippers or tines which excavate earth from the ground so that it can be scooped up by the rest of the chute and transferred to the off loading end thereof.
The base section preferably includes a concave or V-shaped lowermost portion which flares upwardly and outwardly to the side walls which then flare upwardly and outwardly at a greater angle
The base section may include a forwardly extending shovel portion.
The shovel portion may be provided with a sharpened front face and may extend across the face of the chute from one side to the other.
The upper face of the shovel may have a generally concave shape with forward most blade portions being located to the sides of the front face.
The guide is preferably arranged directly behind the cutting means.
It is preferred that the chute side walls are aligned with left and right side cutting devices respectively.
The chute may include a slewing section to enable excavated earth to be off loaded to one or both sides of the is trench which is dug.
It is preferred that the cutting means is fixed in position in relation to the chute so that both the chute and the cutting means are tiltable together.
It is preferred that the cutting means act to cut through earth and the chute acts to scoop up earth on either side of the cutting means approximately to the depth to which the cutting means have cut.
The apparatus may include a height adjustment means to vary the depth at which a trench may be dug.
The chute may include two channels which direct earth to either side of the trench as it is being dug.